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Re: [TowerTalk] TV antennas on HF towers

To: "Tower and HF antenna construction topics." <>
Subject: Re: [TowerTalk] TV antennas on HF towers
From: "Roger (K8RI)" <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Wed, 28 Apr 2010 00:13:02 -0400
List-post: <">>

Charles Coldwell wrote:
> I've heard of/read about people who put television antennas (for
> receiving  OTA broadcast TV) at the top of towers that are also used
> for HF antennas.  Does this risk blowing out the receiver in the TV if
> it picks up harmonics from the HF transmitter?  I suppose one could
> use a low pass filter on the transmitter/amplifier output, but I would
> still expect to get some RFI on the TV.
> Does anyone have any experience with this sort of setup?
Yup! Lots.

With the first one  using the High/Low VHF and UHF combination there 
were no problems.
In the second the *two* UHF antennas (the one pointing South is 
difficult to see) both have remote preamps at the antennas and are used 
for both VHF and UHF.  The antennas are about 30-35 feet below the 144 
and 440 arrays and about 20' above the top of the 144/440 diamond 
vertical.  That high they do a good job of picking up VHF. 

I have no filters in the system. No low pass on the ham rigs and no high 
pass in the TV system.  I've been doing this for over 20 years with 
several analog sets and a 40" LCD HD TV.  HOWEVER, I do lose a preamp 
every few years due to lightning.  The C-band dishes are gone, but we 
still use the DISH Network for satellite which for the last 7 years has 
been mounted at roughly 25' on the tower. That coax runs in the same 
conduit as the coax to the ham antennas.   The only interference I've 
had was on channel 12 analog when the 2-meter array was pointed due 
South  aligning it directly with the South pointing UHF antenna and I 
run the legal limit on all bands. It doesn't seem to bother the digital 
set where there is only one VHF channel left.

I would point out this is one of those cases where YMMV highly and 
caution would be advised.


Roger (K8RI)

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